Wellhead equipment is a device installed at the wellhead to control the pressure and direction of gases, liquids (oil, water, etc.). It is equipped with casing and tubing, and seals the tubing and casing as well as the annulus of each layer of casing during oil and gas drilling. It is usually composed of casing head, anti spray device group, four-way and bypass fittings. Wellhead device is a specialized equipment for oilfield operations, which is a control device widely used for controlling oil and gas well surface and safety valves.